From: Eric Dumazet <edumazet@google.com> mainline inclusion from mainline-v6.19-rc6 commit 3879cffd9d07aa0377c4b8835c4f64b4fb24ac78 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13510 CVE: CVE-2026-22999 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Fixes qfq_change_class() error case. cl->qdisc and cl should only be freed if a new class and qdisc were allocated, or we risk various UAF. Fixes: 462dbc9101ac ("pkt_sched: QFQ Plus: fair-queueing service at DRR cost") Reported-by: syzbot+07f3f38f723c335f106d@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/6965351d.050a0220.eaf7.00c5.GAE@google.com/T/... Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com> Link: https://patch.msgid.link/20260112175656.17605-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- net/sched/sch_qfq.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c index 2e91207dabf0..59d21b5e8ad1 100644 --- a/net/sched/sch_qfq.c +++ b/net/sched/sch_qfq.c @@ -532,8 +532,10 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, return 0; destroy_class: - qdisc_put(cl->qdisc); - kfree(cl); + if (!existing) { + qdisc_put(cl->qdisc); + kfree(cl); + } return err; } -- 2.25.1